Emerald cut length to width ratio and light return

[caratsearcher]

Emerald/ step cut experts - please weigh in!

I have been searching for a while now for a squarish emerald cut diamond (not an asscher though). My sweet spot seems to be for stones with a ratio of 1- 1.15 - 1- 1.25.

My first problem is that I cant seem to find many emerald cuts with this ratio, and my second problem is that when I do find one they don't always have the best cut parameters and light return.

Having studied the cut guidelines for emerald cuts on this site, it seems to suggest that the length to width ratio is not an essential indicator of cut quality and is more down to personal preference. I have been searching with some of the Pricescope sponsored vendors and also a couple of other vendors who have been recommended on this site.

One vendor in particular (they provide lots of emerald cuts with photos, videos and ASETs online) told me that he has never seen an ideal cut emerald with a ratio lower than 1 - 1.3 and that I am unlikely to find one. Is this true? Is there something magical about having a more elongated stone which allows for better light return? If I just keep searching for the diamond with my preferred ratio am I going to have to sacrifice my wish for a top performing stone?

 

[tyty333]

Not an expert but why dont you give people your required specs/budget and let PSers find you some stones?

 

[caratsearcher]

Not an expert but why dont you give people your required specs/budget and let PSers find you some stones?

Thanks for the suggestion, I may well do that But first I would like to get an answer to my question about whether an emerald cut with L/W ratio of 1.1 - 1.25 can still have ideal light performance. If the answer is no then I may need to re-think my criteria for the search.

 

[Mayk]

https://www.pricescope.com/wiki/diamonds/emerald-cut-diamondI

I was able to find a very nice EC with a 1.22 ratio and it scored well on the parameters for a well cut diamond.

The stone you are looking for is out there. A number of people here are experts and they can find what you are looking for. If you provide a budget.

Note- most would not recommend K for an E ring. But everyone will recommend an ASET.

GIA#51511211269
8.13 x 6.63 x 4.28 (ratio 1.226)
2.03 ct K color IF Clarity
Polish: Excellent
Symmetry: Very Good
Fluorescence: Faint
Table: 67% (within premium cut range)
Depth: 64.5% (within premium cut range)
Girdle: Medium

 

[caratsearcher]

https://www.pricescope.com/wiki/diamonds/emerald-cut-diamondI

I was able to find a very nice EC with a 1.22 ratio and it scored well on the parameters for a well cut diamond.

The stone you are looking for is out there. A number of people here are experts and they can find what you are looking for. If you provide a budget.

Note- most would not recommend K for an E ring. But everyone will recommend an ASET.

GIA#51511211269
8.13 x 6.63 x 4.28 (ratio 1.226)
2.03 ct K color IF Clarity
Polish: Excellent
Symmetry: Very Good
Fluorescence: Faint
Table: 67% (within premium cut range)
Depth: 64.5% (within premium cut range)
Girdle: Medium

Mayk, that is a beautiful ring! Your centre stone has that chunky look which I love and it certainly looks like it has loads of life.

I'm feeling very encouraged! Im going to post my specs and see what the experts can come up with. I'd still love to see examples other beautifully cut ECs with these squarer proportions. Does anyone else have any pics to share of their beautiful ECs with L/W ratio of between 1.1 and 1.25?

 

[Mayk]

Here is another fabulous chunky EC

[URL='https://www.pricescope.com/community/threads/my-5-yr-anniversary-upgrade-2-52-emerald-cut-diamond.187820/']https://www.pricescope.com/community/threads/my-5-yr-anniversary-upgrade-2-52-emerald-cut-diamond.187820/[/URL]

Here's one at DBl. I wish is wasn't an Si1. It's nice.

http://www.diamondsbylauren.com/index.php/jewelry/loose-colorless-diamond-94ct-g-si1-emerald-cut-gia-dramatic-shape-r5122

Disclaimer... I'm Not one of the experts. You want Gypsy or Chrono or Diamondseeker to weigh in...and a few others but when they start talking P3 issues the shade comes down on my skill set.

One more from DBL. 1.18 ratio. The experts can find chunky for you.

http://www.diamondsbylauren.com/index.php/jewelry/diamond-ring-77ct-g-vs1-emerald-cut-three-stone-diamond-ring-gia-r6536

 

[diamondseeker2006]

Mayk has a gorgeous one, and I'd love to have a similar EC to hers. Truly, you can't always go by the numbers on any fancy cut diamond. You could have two diamonds with the same basic measurements and one have much better light return than the other based on how the facets are cut. So the answer to your question is that you can have good light return with ratios smaller than 1.3, because you can get excellent light return at 1.0, which is an asscher! I also love the ratios at or under 1.3. But they are hard to find. Great emerald cuts are hard to find, period. It can take a lot of time. I have been casually looking for months and have not found one within the specs I want and with a great cut (I also like smaller tables). So it takes patience above all else.

There aren't many ECs online with pictures other than James Allen. Good Old Gold has a few. That makes it harder to search since it is impossible to narrow down the stones without seeing them.

 

[caratsearcher]

https://www.pricescope.com/wiki/diamonds/emerald-cut-diamondI

I was able to find a very nice EC with a 1.22 ratio and it scored well on the parameters for a well cut diamond.

The stone you are looking for is out there. A number of people here are experts and they can find what you are looking for. If you provide a budget.

Note- most would not recommend K for an E ring. But everyone will recommend an ASET.

GIA#51511211269
8.13 x 6.63 x 4.28 (ratio 1.226)
2.03 ct K color IF Clarity
Polish: Excellent
Symmetry: Very Good
Fluorescence: Faint
Table: 67% (within premium cut range)
Depth: 64.5% (within premium cut range)
Girdle: Medium

Mayk - I just checked out your thread for this ring - it really is a beauty. You obviously shopped for a while before finding this one. Did you notice much difference in colored light return when the table % was smaller or greater than the depth %? How much fire Vs white light return do you see in your diamond? I am wondering whether the table & depth % relationship is that important when shopping for this kind of EC as far as colored light return is concerned?

 

[Mayk]

https://www.pricescope.com/wiki/diamonds/emerald-cut-diamondI

I was able to find a very nice EC with a 1.22 ratio and it scored well on the parameters for a well cut diamond.

The stone you are looking for is out there. A number of people here are experts and they can find what you are looking for. If you provide a budget.

Note- most would not recommend K for an E ring. But everyone will recommend an ASET.

GIA#51511211269
8.13 x 6.63 x 4.28 (ratio 1.226)
2.03 ct K color IF Clarity
Polish: Excellent
Symmetry: Very Good
Fluorescence: Faint
Table: 67% (within premium cut range)
Depth: 64.5% (within premium cut range)
Girdle: Medium

Mayk - I just checked out your thread for this ring - it really is a beauty. You obviously shopped for a while before finding this one. Did you notice much difference in colored light return when the table % was smaller or greater than the depth %? How much fire Vs white light return do you see in your diamond? I am wondering whether the table & depth % relationship is that important when shopping for this kind of EC as far as colored light return is concerned?

I looked at several including a smaller one. My EC faces up very white and I only see tint in certain lighting. Outside I get lovely flashes. Now is it related to the table and depth I am not sure. I just tried to keep the ideal parameters in the back of my mind as I looked. I also shopped local B&M stores. I was able to look at a very nice 2 ct I and he had done to compare when I was deciding on size. But I never intended to buy from them. David at DBL found my diamond.

 

[Rockdiamond]

Hi All,
Caratsearcher- The first question I'd ask is what is "ideal light performance" for an emerald cut?
The answer? Whatever YOU think is ideal.
There really is no established parameters that are agreed-upon by experts – and based on the over my 40 years experience, it's not agreed-upon by non experts who love Emerald cuts either.
Again from personal experience: I might look at 20 emerald cut diamonds before I find one that I like.
I have seen many stones with the LxW ratio that you're seeking that I considered to be very beautiful and perform very well in my opinion. Again from personal experience – I'd say it's harder to find a really nice one that's longer, as opposed to more square as you are seeking.
For me, the corners have a huge impact as they affect the entire facet pattern on the pavilion.
In terms of the numbers –table and depth are just about irrelevant when selecting. Remember, two stones with the exact same length by width, depth percentage, and table percentage will look totally different simply based on the size of the corners

mayk– I'm sure you somehow forgot about me when you said that "everyone" would recommend an ASET
In fairness – we never had one of your stone, nor did we ever need one.

 

[Mayk]

Hi All,
Caratsearcher- The first question I'd ask is what is "ideal light performance" for an emerald cut?
The answer? Whatever YOU think is ideal.
There really is no established parameters that are agreed-upon by experts – and based on the over my 40 years experience, it's not agreed-upon by non experts who love Emerald cuts either.
Again from personal experience: I might look at 20 emerald cut diamonds before I find one that I like.
I have seen many stones with the LxW ratio that you're seeking that I considered to be very beautiful and perform very well in my opinion. Again from personal experience – I'd say it's harder to find a really nice one that's longer, as opposed to more square as you are seeking.
For me, the corners have a huge impact as they affect the entire facet pattern on the pavilion.
In terms of the numbers –table and depth are just about irrelevant when selecting. Remember, two stones with the exact same length by width, depth percentage, and table percentage will look totally different simply based on the size of the corners

mayk– I'm sure you somehow forgot about me when you said that "everyone" would recommend an ASET
In fairness – we never had one of your stone, nor did we ever need one.

David you did give me this. I saved it. Not an ASET like JA but the DBL version. I got to see it in real life and I was hooked.

 

[Rockdiamond]

Someone has a much better memory than I

We have actually upgraded our ASET picture taking capabilities.....

But the pic does kinda prove a point.
Would many on PS recommend buying a stone with that ASET?
Likely not.
However I honestly believe that if people actually saw the stone in real life, they'd likely highly recommend it based on it's real life Light performance.

 

[chrono]

You are correct that ratio is a personal preference and has little bearing on the light return performance.

 

[diamondseeker2006]

Someone has a much better memory than I

We have actually upgraded our ASET picture taking capabilities.....

But the pic does kinda prove a point.
Would many on PS recommend buying a stone with that ASET?
Likely not.
However I honestly believe that if people actually saw the stone in real life, they'd likely highly recommend it based on it's real life Light performance.

I am pretty much in agreement after looking at MANY EC ASETs that people cannot have the expectation that EC ASETs will appear anything like an ideal cut round does. I think Mayk's diamond is beautiful, and I also think the JA stones had ASETs indicating the diamonds were worth looking at. I would avoid ASETs showing a lot of the background color indicating large mounts of leakage, so an ASET is still useful for me in screening. Plus that one of Mayk's stone shows what a pretty cut it is. Finding a stone with a < 1.25 ratio is hard enough, but expecting a perfect ASET image bascially means it will be impossible.

 

[Karl_K]

Would many on PS recommend buying a stone with that ASET?

The ASET shows that diamond has a lot of potential.
Red on the verge of blue is a sweet spot for the long virtual facets.
The windmill angles could be better but they likely work well.
Looking at the ASET it is no surprise to me it would be picked by eye over the market norm.

 

[Rockdiamond]

Great points Karl- of course I would expect you to see the potential in the ASET.
Where I was coming from was:
1) quality of the image is horrible
2) there's some decent sized areas of leakage shown. That could have to do with the image. Even with the newer desk model, it's still kinda hard to get the stone's table sitting at a 90 degree angle to the lens for a picture.
Basically, my point is that an ASET image like that might have people thinking the leakage is problematic- yet leakage is not a negative in this stone.

 

[Karl_K]

My sweet spot seems to be for stones with a ratio of 1- 1.15 - 1- 1.25.

My first problem is that I cant seem to find many emerald cuts with this ratio, and my second problem is that when I do find one they don't always have the best cut parameters and light return.

Over 1.05 is considered off make for a SE and under 1.3 is considered off make for an EC.
I like ECs around 1.2x a lot but finding a nice one can be very hard.

 

[Rockdiamond]

I agree with Karl's point 1.30 is the "traditional" ratio for a matchbox rectangle.
There's also matchbook rectangle- which although they are more rare, are out there- and I also think any ratio from 1:1 to 1.2:1 can look amazing.
In fact, there's probably a greater challenge creating balanced light performance in a 1.3:1 as compared to a 1.2:1.

 

[Karl_K]

In fact, there's probably a greater challenge creating balanced light performance in a 1.3:1 as compared to a 1.2:1.

yep very much so.

 

[Gypsy]

Hi All,
Caratsearcher- The first question I'd ask is what is "ideal light performance" for an emerald cut?
The answer? Whatever YOU think is ideal.
There really is no established parameters that are agreed-upon by experts – and based on the over my 40 years experience, it's not agreed-upon by non experts who love Emerald cuts either.
Again from personal experience: I might look at 20 emerald cut diamonds before I find one that I like.
I have seen many stones with the LxW ratio that you're seeking that I considered to be very beautiful and perform very well in my opinion. Again from personal experience – I'd say it's harder to find a really nice one that's longer, as opposed to more square as you are seeking.
For me, the corners have a huge impact as they affect the entire facet pattern on the pavilion.
In terms of the numbers –table and depth are just about irrelevant when selecting. Remember, two stones with the exact same length by width, depth percentage, and table percentage will look totally different simply based on the size of the corners

mayk– I'm sure you somehow forgot about me when you said that "everyone" would recommend an ASET
In fairness – we never had one of your stone, nor did we ever need one.

David you did give me this. I saved it. Not an ASET like JA but the DBL version. I got to see it in real life and I was hooked.

Just saw this. And I've seen the stone in person. This ASET is a strong one. I would have recommended it. And the in person appearance is stunning.

 

[caratsearcher]

I have the option to buy this diamond, with ratio of 1.18. There is no option for an ASET and I have no idea of crown angles, although the crown does look to be quite steep. The table is 62 and depth 66. From the pics, is this a good EC in terms of cut?

 

[Gypsy]

Got potential. But you would know better than we do. What did you see? Did you like it?

 

[caratsearcher]

Overall the stone was very pretty and gave off a lot of white and colored flashes when it moved.

The symmetry is rated excellent but I had problems trying to get the factets to light up in a symmetrical way, if that makes sense. It had a great amount of fire which was very pretty so that was a plus. But it was difficult to judge the white light return because every time I got the long facets on one side of the diamond to light up it seemed like the ones on the other side went dark. Having said that, there werent any areas which stayed permanently dark, they did alternate between light and dark depending on the viewing angle.

At some angles it looked as though the crown angle was too steep or something, because 2 sides of the crown would start to look a little "flat" whilst the other two sides would light up (see picture 4).

I was also confused that sometimes the diamond appeared to have many small facets (as in photos 2 & 4) giving a thin step pattern and sometimes it appeared to have fewer, chunkier facets giving a thick step pattern.

This is the first squarish emerald cut I have had the chance to examine in person and photograph in various lighting conditions so I dont have a lot to compare it to.

Are the above observations to be expected and completely normal, even in a well performing stone, or do they indicate too much light leakage?

 

[Gypsy]

Symmetry on a lab report doesn't refer to optical symmetry. It refers to the cutting of the stone. So you can have the effect you describe of facets that light up in a random instead of symmetrical pattern.

Did tbat bother you? Or was it part of the stones personality and you liked it?

That's the thing with fancies-- theh have distinct personalities. Like cats. Either it works for you or it doesn't. It's part art. You can't quantify a connection.

I once had a friend deciding between 2 OECs which we met for lunch to evaluate. One was higher color, perfectly round and had a great ASET. The other had a Little wonk to the shape, was warmer in color, and tbe Aset showed issues. We both prefered the winky stone. It captivated us, while the other one--more technically perfect--did not.

That's how it is witb ECs too.

So it really is a matter of what works for you and what doesn't.

 

[caratsearcher]

Symmetry on a lab report doesn't refer to optical symmetry. It refers to the cutting of the stone. So you can have the effect you describe of facets that light up in a random instead of symmetrical pattern.

My brain can't get itself around this - how can excellent cutting symmetry not lead to excellent optical symmetry?

 

[Gypsy]

Other people can explain it better.

This is from Rhino of (GOG):

"When it comes to symmetry grading the labs look at the exterior symmetry of the diamond and check those things that apply to external symmetry grading (meeting of facet points, sloping of table, how centered the culet and table is, etc.) so slight deviations in that type of symmetry is not detectable to the eye. The type of symmetry that impacts the beauty of the diamond most is it's 3-dimensional symmetry."

And the labs do not look at 3-dimensional symmetry for fancies.

Another post by Rhino (of GOG):

"Well ... here''s the Rhinocerotic ''nutshell'' version. Lab graded symmetry/ie. physical symmetry is an analysis of how well and aligned all facet points meet as the exterior of the diamond is analyzed. This is also referred to as meet-point symmetry but there are other features that are examined in the lab such as off centered table, off centered culet, wavy girdle, etc. We have the entire chart of these in our tutorial as well as a high definition video demonstrating these features under a microscope.

Optical symmetry on the other hand is an examination of the optical alignment of the reflections observed within the diamond particularly through optical devices."

Hope that helps. Basically, there are different types of symmetry. And Optical symmetry is different from physical. One looks at the 3D stone (Optical) the other looks at the physical alignment of the facets of the stone. And one doesn't equal the other.

 

[caratsearcher]

Wow - thanks for that explanation Gypsy. I guess that makes sense now.

Ive been sent the following photos for a diamond which someone found for me on another thread. I am noticing a lot of darkness in the second photo which doesnt look attractive to me, although the first photo looks better. What is happening with the light return in the second photo to create this large dark area? And would I expect to see this effect in real life?

 

[Karl_K]

Wow - thanks for that explanation Gypsy. I guess that makes sense now.

Ive been sent the following photos for a diamond which someone found for me on another thread. I am noticing a lot of darkness in the second photo which doesnt look attractive to me, although the first photo looks better. What is happening with the light return in the second photo to create this large dark area? And would I expect to see this effect in real life?

obstruction,, ie reflection of the camera lens..
No way to say for sure if its an issue with less obstruction when viewed in person from the information provided.

 

[Gypsy]

Karl is the step cut expert. I'm just a minion.

 

[Gypsy]

Look at this: https://www.youtube.com/watch?v=Ac1IebZNmvQ


This is pretty much my dream stone. You can see how the facets light up and even go dark at times. But its just a breathtaking stone. That's what you want, if you can find it

And now, AFTER you see the video, look at this: https://www.victorcanera.com/diamonds/gz5i55-3.05-f-vs1-emerald-cut See the ASET. Can you see the corresponding effect on the video?